JuneiSgg-] CaSEY : O.V AMERICAN COCCINELLID^. 77 



These forms are all virtually similar in ornamentation to the com- 

 mon yz/jv/Az/r/^. 



Hippodamia Chev. 

 The species of this genus are rather numerous, and constitute by far 

 the larger part of the tribe ; they are frequently closely allied among 

 themselves and are common to the arctic and subarctic faunas of both 

 hemispheres, although poorly represented in the paltearctic provinces. 

 The sternal and ventral plates lose all value in a generic sense, and the 

 Adonia of Mulsant, must consequently be suppressed, as suggested by 

 Crotch. Sometimes, as in parenthesis and apiealis, both the' sternal 

 and ventral plates are distinct and as perfect as in Anisosticta. In 

 obliqiia and eonvergens, also, they are similar, though more feebly out- 

 lined. In leeontei, qin?iqi/esi'gnata, with related species, and in the 

 siniiata group, the sternal plates become obsolete or very indistinct, but 

 the ventral are still complete or very nearly. In glaeialis the sternal 

 plates are completely obliterated and the ventral are only represented 

 by an oblique and isolated external line, and finally in tredeeempunc- 

 tata, the type of the genus, both plates become obsolete. 



Hippodamia (^Adonia') variegata of Goeze, {constellata Laich.), is a 

 European species which is said to occur within the United States ; this is 

 probably an error, however, and it is omitted from the following table 

 of the American species known to me by actual examples. The 

 sternal and ventral plates are exactly as va. parenthesis and apiealis, but 

 in habitus and ornamentation it agrees with the majority of species 

 much better than they : — 



Pronotum with a broad pale lateral border enclosing an isolated black dot or dot- 

 like spur from the central black area, the latter without trace of the usual white 

 discal diverging lines ; elytra each very constantly with six rounded black dots, 

 and also a small common scutellar spot ; femora black, the tibice and ^tarsi pale 

 throughout ; claws rather thicker and more feebly arcuate than usual. Length 

 4.3-5.3 mm.; width 2.4-3.3 "^i"- Europe, Siberia and the United States. 



{tibialis Say] 1 3-punctata Linn. 



Pronotum with a narrower white lateral margin which is intruded upon by a more 

 or less pronounced angulation of the central black area, occasionally completely 

 dividing the white area, in which case the white near the basal angles also fre- 

 quently disappears ; legs black throughout, the anterior sometimes in part pale, 



especially in those species with distinctly formed sternal and ventral plates 2 



2 — Pronotum without trace of a median white spot at the basal margin ; sternal and 



abdominal plates very variable in development ■ 3 



Pronotum with a white or whitish median spot at the basal margin ; sternal and 

 abdominal plates both distinct, the latter complete but short, extending to about 

 the middle of the segment 21 



